Around 10 minutes into trading, the Dow Jones Industrial Average was down 0.1 per cent at 40,518.87, and the S&P was 0.1 per cent lower at 5,536.08.
The Nasdaq slipped 0.2 per cent to 17,566.08.
However, all three major Wall Street indices are on track to end the week in the green at the end of a week in which fresh economic data pointed to a continued slowdown in annual inflation, low levels of jobless claims, and resilient retail sales.
"The stock market had another good day on Thursday, drawing some motivation from the pleasing initial jobless claims and retail sales data, which seemed to silence the hard-landing worries," Briefing.com's Patrick O'Hare wrote in a blog post before markets opened on Friday.
He added that "it shouldn't come as much of a surprise to hear that the equity futures market is experiencing a little bit of indigestion this morning".
Among individual stocks, packaging company Amcor was trading down more than six per cent after it reported earnings results.
And shares of US semiconductor equipment maker Applied Materials fell more than four per cent after it forecast revenues slightly above Wall Street expectations.
